MOTOR AND CYCLE.

Taranaki Daily News, 17 July 1918, Page 7

MOTOR AND CYCLE.

NEWTS AND NOTES, SPJiIGtALISIKG IN .UNITS. Apparently, it does not pay the , American car manufacturer to make his own engine. Excepting tho few very largo concerns, almost all the other makers buy their units from specialists. The Seripps-Boolh firm is the latest concorn_ to dispose of its engine plant. In America there is no false prido taken in being aible to say that a certain car is made under one roof. One may say that the large concerns who can make this statement are a consolidated group 'of unit factories under one name, and that the system of specialisation is not departed from. Most of the successful concerns in America, including the Ford, commenced operations by buying their units. The reluctance of British manufacturers in the past to depart from their conservative methods in this direction, although perfectly sound so far as the production of an article is concerned, places them at a serious disadvantage in the overseas markets, where American cars are sold at a low figure. RADIATOR FAN BELT. There are various forms of adjustment for radiaitor fan "belts, for example slide, eccentric and pivoted bracket arrangements. A recent adaptation from motor-cycle practice ia tho use of an aSjustalble pulley, one flange of which can be screwed close to the fixed flange, thus altering the diameter. WEIGHT OF MOTOR CYCLE PAETS. Motor cyclists will be interested to know the approximate percentages of certain parts Of a medium powered single cylinder machine in relation to the total weight. The engine usually weighs about 25 per cent, frame II per cent, feat complete 4 per cent-, wheels with tyres 16 per cent,, transmission 16 per cent-, petrol tank 4 per cent., mudguards 4 per cent, magneto with driving gear 5 per cent-, saddle 4 per cent., footrests 2 per cent., brakes 1 iper cent., silencer I per cant., controls 1 per cent., carburettor i per cent. The handlebars and cool bag make up the other 8 per cent. GETTING OVER FREIGHT DIFFICULTY, Owing to the rail freight difficulties in getting ears to the shipping porta, many of the leading car makers are now sending away relays of cars which are driven under their own power to their destination. Thousands of new cara are now to be seen journeying along the Lincoln Highway either in the direction of San Francisco or New York. In a way this form of delivery to the seaboard is a good trial test and enables all need of adjustment to bo carried out by the drivers under actual touring conditions. Most of the cars of the various makers travel in groups and average about 20 m.p.h. DIFFERENTIAL GEAR. , In trying tt> understand the motor ear differential gear some people find it hard to see why, at a corner, one wheel really does turn faster than another A very simple experiment is to place a light ear \ on a level road with the front wheels straight; then, with a foot rule and a I piece of chalk, make a mark at the back | of each rear wheel tyre, say, 1 inch front the ground. If the car is now pushed forward for a few feet, it will be seen that as the wheels turn the marks rise with them, tout remain in the same relative position on each wheel- The back wheels are, therefore, turning at exactly the samo speed when the car is going , straight. Now set the front wheels j pointing sharply to the left, and as it does so the mark on the right wheel will 1 move further than that on the left, thup , showing that this wheel lias turned more quickly than the other. But why has it . done so! For answer one can take the practical illustration of walking round a sharp left-hand curve on a road. If i one keeps close in to the left-hand side s all the. way and counts one's eteps, and then repeats the process, keeping to the right-hand side, it will be found that in this latter case one has taken a good many more steps, and so covered more ground. On a smaUe'r scale, it is exactly tho same with the wheels; the outer one , has turned round more and the mark [ has moved further along its circumfer- ( ence,- because this wheel has had to pass ; over more ground than the inner one. The function of the differential is to allow this variation in speed to occur whenever the conditions require it, other- ■ wise, if a car has no differential, the driving wheels are forced to revolve at x exactly equal speeds, and as at a corner tho inner one does not require to turn in its natural rolling motion as quickly ' as tiie outer, it is formed round and \ obliged to slip and scrape over tho sur- ; face until the car retums to an approxi- ' mately straight course. A simple and effective style of hood for a light car has been noted in use by ' the writer. It is on tho principle of the ' roller blind, and its outstanding feature | is its extreme neatness and simplicity. There is a rounded depression just behind tile seat of the two-seater car in which tho cylinder containing the hood rests. The erection is very simple. There are two Y shaped side supports held by strong catches. Tho canvas covering is then pulled out of its casing ' and fastened over studs at the end of the stays, the front of tho hood being secured in position by two straps. The • canvas is held absolutely taut and side curtains can be fitted if required. It certainly seems the acme of simplicity, and when not in use is a great improvement, from an appearance point of view as with the ordinary system. Again this system of hood avoids the chaffing and cutting through of covering incidental to the type of hood now in general use. It is estimated by competent authorities that the majority of automobile accidents are Hie results of side slips due to defective braking. It must not be inferred, however, that the brakes themselves are in all cases defective, but rather that their proper adjustment has not been maintained, and that they were not used with judgment. The operation of a brake necessarily invokes wear, so that this cannot be charged as a defect against the manufacturer; and it follows that systematic and periodical attention should be given to the brakes to keep them adjusted so that they will operate effectively. Too many car owners, however, have neither the ability nor tho inclination to take care of their brakes, or to use them with discretion, and consequently are a standing menace to tho community.